[libc-commits] [libc] [libc] implement stdc_leading_zeros_u* for stdbit.h (PR #79669)

[Schrodinger ZHU Yifan via libc-commits]

SchrodingerZhu wrote:

https://snapshots.sourceware.org/glibc/trunk/latest/manual/html_node/Bit-Manipulation.html
Maybe not in this commit. Consider define the macros:
```
Macro: __STDC_ENDIAN_LITTLE__
This macro represents little-endian storage.

Macro: __STDC_ENDIAN_BIG__
This macro represents big-endian storage.

Macro: __STDC_ENDIAN_NATIVE__
This macro equals __STDC_ENDIAN_LITTLE__ if integer types are stored in memory in little-endian format, and equals __STDC_ENDIAN_BIG__ if integer types are stored in memory in big-endian format.
```

https://github.com/llvm/llvm-project/pull/79669